Summary
I am an interdisciplinary nanoscientist with a broad range of experience in 2D material synthesis, nanofabrication, and advanced characterization techniques. My research integrates concepts from mechanical engineering, materials science, and condensed matter physics to explore the fundamental properties of materials at the nanoscale with an emphasis towards energy harvesting and flexible electronics applications for a sustainable future.
Research Themes
Ferroelectric materials have spontaneous and switchable electrical polarization, which originates from the non-centrosymmetry in the crystal structure. The broken crystal symmetry makes them piezoelectric, pyroelectric, and photovoltaic. Ferroelectrics are useful in low-power memory, sensing, energy harvesting, and micro-nano electromechanical systems. Despite the opportunities, most conventional three-dimensional ferroelectric materials suffer a great challenge at nanoscale. The polarization becomes unstable at less than 10 nm thickness, mainly due to the surface dangling bonds. One potential solution to this problem is to utilize 2D ferroelectrics, which are predicted to be stable down to a monolayer due to the absence of dangling bonds.
My research focuses on utilizing the distinct properties of 2D materials, such as reduced dimension, enhanced flexibility, and van der Waals bonds in the out-of-plane direction, to probe ferroelectricity at the 2D limit.
Friction and slip at the material surface plays an important role for confined channel at the nanoscale. This collaborative project explores how the underlying substrate, liquid ordering, and electric field dynamically tune the friction of monolayer graphene.Â
Raman spectroscopy is a strong characterization tool for probing the vibration of molecules, which essentially provides information about the quality, strain, doping, and crystal structure of the material. One drawback for traditional Raman spectroscopy is the diffraction limited spatial resolution, typically 200-300 nm. So, any feature less than the diffraction-limited laser spot is not captured by this technique. In this regard, tip-enhanced Raman spectroscopy, generating a localized high intensity electric field using the plasmon resonance by the tip of a scanning probe, overcomes this limitation and provides information with 10-20 nm resolution.
In this project, I am utilizing this technique to probe the anisotropic and nonuniform strain in 2D materials.
Low-dimensional materials show intrinsically different mechanical and fracture behavior compared to their bulk counterparts. Atomistic simulation and data-driven machine learning based approach are useful tools to study the mechanical properties of these materials.
I guide and supervise undergraduate mentees to use molecular dynamics simulations to understand the mechanical response of various low dimensional materials.